A high school student from California won a $100,000 scholarship Monday for research that created a tiny particle she likened to a "Swiss army knife of cancer treatments" because of its precision in targeting cancer tumors.

Angela Zhang, 17, of Cupertino, Calif., won top individual honors at the Siemens Foundation's annual high school science competition, which announced winners in Washington. Top team honors went to a pair of students from Oak Ridge, Tenn., for their research using gaming technology to analyze the motion involved in walking. Cassee Cain and Ziyuan Liu, both 17, will share a $100,000 scholarship.

Six individuals and six teams were competing for the awards, which are in their 13th year. Zhang, the only female individual finalist, said her research was in part motivated by her family. Her great grandfather had liver cancer and her grandfather died of lung cancer when she was in seventh grade.

"I asked, `Why does this happen. Why does cancer cause death? What are we doing to fix this and what can I do to help,"' said the Monta Vista High School senior.

Zhang said the particle she designed improves on current cancer treatments because it delivers a drug directly to tumor cells and doesn't affect healthy cells around it. The particle is also able to release a drug when activated by a laser. The idea is still years away from being used in patients, however.

Zhang says it could take 25 years between clinical trials and other steps before her research is helping patients.

The team winners, Cain and Liu, got their inspiration from video game technology normally used to track a person's movements for dance, sport and fitness games. The pair of seniors from Oak Ridge High School developed software that uses the technology to analyze the way a person walks. They hope their software can ultimately be used to help people who wear prosthetic limbs improve their walk. Currently, people who have prosthetic limbs generally have to travel to labs to get that kind of help, but Cain and Liu say that because their software uses readily available technology it could be more widely used and also taken to developing countries.

"Anything that has a joint we can track, really, just depending on what we're interested in or what the doctor is interested in," said Cain, who is also the drum major in her high school marching band and a costume designer for the drama club.

The runners-up in the team and individual competitions went home with $50,000 scholarships.

Second place in the individual competition was Brian Kim of New York, who studied ways to more efficiently pack objects into a space. The second-place team winners were Edgar Wang, Wayne Shu and Justin Yuan of Troy, Mich., whose research could help treat Alzheimer's disease and stroke.

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